Our goal is the demonstration of regulatory genes in a eukaryote. The three hemoglobins of the brine shrimp, Artemia salina, are an ideal system for the assay of regulatory mutations because the hemoglobins are inducible, they are not essential for life, changes in quantity of hemoglobin can be detected in the living transparent animal, and the hemoglobins are easily isolated for biochemical studies. Classical genetics studies will show if the structural and regulatory loci are linked and if the regulatory mutation is pleiotropic. We will map the location of the variants on the sex chromosomes by means of X-chromosome deletions. We will attempt to isolate Artemia fat cells (which might be expected to synthesize and degrade hemoglobin) and the shell gland cells (reported to excrete hemoglobin). We hope to demonstrate that the fat cells synthesize hemoglobin and that shrimps which differ in gene-determined threshold of hemoglobin induction have fat cells which show different degrees of hemoglobin synthesis in response to carbon monoxide and low oxygen (as do the animals from which the cells are derived).